Elucidating sex and gender differences in diabetes: a necessary step toward personalized medicine

Research on Women's Health: Ready for the Future

The National Institutes of Health (NIH) Office of Research on Women's Health (ORWH) was established in 1990. With the completion of the office's 30th anniversary year, we look back and recount some of the key events and overall zeitgeist that led to ORWH's formation, and how it became the focal point at the nation's primary biomedical research agency for coordinating research on science to improve the health of women. We discuss ORWH's mission and signature programs and the bold vision that drives the NIH-wide strategic, interdisciplinary, and collaborative approach to research on women's health and efforts to promote women in biomedical careers. Also discussed are several of the many scientific advances in research on the health of women, policy innovations and their effects, and career advancements made by women in medicine and related scientific fields. We also highlight key challenges for the health of women, the need to continue pushing for equity in biomedical research careers, and NIH's approach to addressing these problems to ensure progress for the next 30 years and beyond.

International feasibility study for the Women's Wellness with Type 2 Diabetes Programme (WWDP): An eHealth enabled 12-week intervention programme for midlife women with type 2 diabetes

AIMS

The current study aimed to examine feasibility of participant recruitment and retention rates for the Women's Wellness with Type 2 Diabetes program (WWDP), and to assess initial efficacy of the program in improving wellbeing outcomes.

METHODS

70 midlife women with type 2 diabetes mellitus (T2DM) participated in a 12-week wellness-focused intervention, the WWDP. The WWDP involved a structured book (with participatory activities), an interactive website and nurse consultations. This study had an Australian and a UK arm. Analyses were conducted using chi-square, McNemar, paired t-test, and Wilcoxon signed-ranks tests.

RESULTS

The attrition rate for the sample was 22.2%. Overall, significant improvement was observed in diabetes distress (DD), diabetes self-efficacy, weight, BMI, menopausal symptoms and sleep symptoms from baseline to program completion at 12 weeks. Australian participants were also more likely to meet fruit recommendation guidelines and had significant waist- and hip-circumference reductions.

CONCLUSIONS

Good retention rates and initial efficacy findings indicated feasibility of the WWDP as a promising 12-week health and wellness program for women with T2DM. They also suggest incorporating a focus on self-efficacy and gendered information may be important in improving wellness and health outcomes related to distress and menopause.

Cardiometabolic risk factors correlated with the incidence of dysglycaemia in a Brazilian normoglycaemic sample: the Baependi Heart Study cohort

BACKGROUND

Dysglycaemia is defined by elevated glucose levels in the blood, commonly characterized by impaired fasting glucose, impaired glucose tolerance, elevated glycated haemoglobin, or diabetes mellitus (DM) diagnosis. The abnormal levels of glucose may occur many years before DM, a condition known as prediabetes, which is correlated with comorbidities such as cardiovascular diseases. Therefore, the aim of this study was to investigate the incidence of prediabetic dysglycaemia and its relationship with cardiometabolic risk factors at a 5-year follow-up, based on an initially normoglycaemic sample in the Baependi Heart Study cohort.

METHODS

The data used comes from the Baependi Heart Study cohort, which consists of two periods: cycle 1 (2005-2006) and cycle 2 (2010-2013). For this study, we excluded those who had fasting blood glucose ≥ 100 mg/dL or were taking anti-diabetic medications at baseline, and those that had diabetes diagnosed in cycle 2. Mixed-effects logistic regression models were used to assess the association between cardiometabolic risk factors and the incidence of dysglycaemia, including a familiar random effect such as a cluster.

RESULTS

The incidence of prediabetic dysglycaemia was 12.8%, and it did not differ between men and women (14.4% and 11.6%, respectively). Two models were analysed to investigate the relationship between cardiometabolic risk factors and the occurrence of prediabetic dysglycaemia. The model that better explained the occurrence of dysglycaemia over the 5 years, after correction, included the waist circumference (WC) (measures and Δ), systolic blood pressure (SBP), HDL-c levels, and age. Although sex was not associated with the incidence of dysglycaemia, women and men showed differences in cardiometabolic risk factors related to glucose impairment: men who developed dysglycaemia showed, in parallel, higher LDL-c levels, TC/HDL-c ratio and DBP measurements; while these parameters remained similar between women who developed dysglycaemia and dysglycaemia-free women, after 5 years.

CONCLUSIONS

In an initially normoglycaemic sample of a highly mixed population living in a traditional Brazilian lifestyle, important cardiometabolic risk factors were associated with the occurrence of prediabetic dysglycaemia, and this relationship appeared to be more important in men. These results provide important insights about cardiovascular risk in prediabetic individuals.

A Guide for the Design of Pre-clinical Studies on Sex Differences in Metabolism

In animal models, the physiological systems involved in metabolic homeostasis exhibit a sex difference. Investigators often use male rodents because they show metabolic disease better than females. Thus, females are not used precisely because of an acknowledged sex difference that represents an opportunity to understand novel factors reducing metabolic disease more in one sex than the other. The National Institutes of Health (NIH) mandate to consider sex as a biological variable in preclinical research places new demands on investigators and peer reviewers who often lack expertise in model systems and experimental paradigms used in the study of sex differences. This Perspective discusses experimental design and interpretation in studies addressing the mechanisms of sex differences in metabolic homeostasis and disease, using animal models and cells. We also highlight current limitations in research tools and attitudes that threaten to delay progress in studies of sex differences in basic animal research.

Low-power laser irradiation in salivary glands reduces glycemia in streptozotocin-induced diabetic female rats

Low-power laser irradiation (LPLI) has been extensively employed to modulate inflammation in vitro and in vivo. Previous reports from our group indicated that LPLI might regulate glycemia in diabetic animals. Diabetes results in chronic hyperglycemia and therefore chronic inflammation by upregulation of inflammatory markers such as the high mobility group box 1 (HMGB1) protein. Thus this study aimed to analyze the LPLI effects upon blood glucose levels, plasma insulin and HMGB1 concentrations in a diabetes experimental rat model. Streptozotocin-induced diabetic rats were irradiated in the salivary glands area with a diode laser applied at 660 nm, 70 mW, 20 J/cm² , 22.4 J, with a spot area of 0.028 cm² and its effects were evaluated. LPLI significantly reduced diabetic rat hyperglycemia, without changing insulin or HMGB1 plasma levels, but possibly by ameliorating the insulin resistance in these animals. These findings suggest that LPLI might have a systemic effect, but more studies are necessary to better understand its mechanisms. Fasting blood glucose measured by peroxidase-glucose oxidase (PGO) method (A), showing a reduction of diabetic animals glycemia after LPLI. LPLI probably reduced the hyperglycemia in diabetes by improving the insulin resistance in these animals (B). C n = 10, CL n = 10, D n = 7 and DL n = 8. Data are expressed as mean ± SD; * P < 0.05 vs. respective control group; # P < 0.05 vs. D group.

Sex Differences in the Renal Function Decline of Patients with Type 2 Diabetes

Aims. We aimed to investigate the sex differences in the renal function decline among patients with type 2 diabetic mellitus (T2DM), focusing on the differences in the risk factors at early stage of renal dysfunction. Methods. A clinic-based retrospective longitudinal study (follow-up duration: 8.1 ± 1.4 years) was conducted to assess the sex differences in the annual estimated glomerular filtration rate (eGFR) change in 344 (247 male and 97 female) Japanese T2DM patients. The sex differences in the risk factors of annual eGFR decline were subjected to linear regression analyses. Results. The mean annual eGFR change was -3.5 ± 2.7%/year in females and -2.0 ± 2.2%/year in males (P < 0.001). Baseline retinopathy and proteinuria were significantly associated with a larger eGFR decline, irrespective of sex, while HbA1c and LDL-cholesterol levels were significantly associated with an eGFR decline in females only. Interactive effects were observed between sex and the HbA1c, LDL-cholesterol, retinopathy, or proteinuria levels on the annual eGFR decline. Conclusions. The increased susceptibility to poor metabolic control seemed to contribute to a higher risk of renal dysfunction in females with T2DM. Our study highlights the importance of aggressive therapeutic intervention to improve metabolic profiles at early stage, especially in females.